package collection;

import java.util.ArrayList;
import java.util.Collection;

public class CollectionDemo1 {
    public static void main(String[] args) {
        Collection c=new ArrayList();
        c.add("one");
        c.add("twe");
        c.add("three");
        c.add("four");
        System.out.println(c);
        System.out.println("集合大小："+c.size());
        System.out.println("是否是空集："+c.isEmpty());

        c.clear();
        System.out.println("集合已清空");
        System.out.println(c);
        System.out.println("集合大小："+c.size());
        System.out.println("是否空集："+c.isEmpty());
    }
}
